This application relates to a single valve that combines the function of a metering valve and a pressure regulating valve.
Modern fluid delivery systems are often provided with a metering valve and pressure regulating valve, which together control the amount of fluid that is delivered to a user. As an example, a fuel supply system for supplying fuel to an engine will include such a metering valve and pressure regulating valve. Fuel is delivered from a positive displacement pump to the metering valve. The position of the metering valve determines the size of a variable flow opening (metering valve window) in the flow path from the pump to engine. The pressure regulating valve senses pressures upstream and downstream of the metering valve window and varies the amount of flow it bypasses back to the pump inlet to maintain the metering window pressure drop at a constant value. The metering valve position is controlled by an engine control. With a fixed pressure drop maintained across the metering window, a selected amount of fuel will be scheduled to the engine as a function of metering valve position.
In the prior art, these two functions have been provided by two separate valves.